Problem: Julia baked $12$ pies for the school bake sale. $10$ were apple pies and the rest were blueberry pies. Complete the number sentences to find how many blueberry pies Julia baked. $12$ pies total $-\, 10$ apple pies $= $
Explanation: $12$ can be separated into two parts: ${10}$ and $?$ We can use subtraction to find the missing part: $12 - {10} = 2$ We can also think about how much more can be added to ${10}$ to get $12$ : ${10} + 2 = 12$ The answer $ 12 - {10} = 2 $ ${10} + 2 = 12$